Today's large liquid-container products, such as both portable and stationary above-ground swimming pools containing water, typically have a drain valve to allow removal of the liquid, either for storage of the portable container or during the winter season for the stationary one. Most of these drain valves require that the user insert his or her hand into the water in order to plug or unplug the drain valve. Further, most of these drain valves are not connectable to hoses for routing the draining liquids to a desired disposal area, instead allowing the liquids to run out directly into the area where the container is located. This can lead to various kinds of property and/or environmental damage, such as in the case of drainage of chlorinated pool water onto landscaping.
A prior art drain valve that is connectable to an ordinary garden hose and thus avoids the latter problem is disclosed in U.S. Pat. No. 6,257,550 (Saputo et al). The valve of Saputo et al has a tubular body with a mating member and a hose connector in communication with each other, the hose connector being disposable along the drain valve passageway and releasably attachable to the valve body by a cap. The hose connector has at least one prong that, when the hose connector is fully inserted into the valve passageway, forces open a drain plug blocking the passageway and allows liquids to drain from the container in which the valve is installed. The plug also has a pull tab and is attached to the drain valve body by a flexible stem. The hose connector can take a variety of forms, allowing it to be connected to either a conventionally sized U.S. garden hose or to the variably-sized hoses found in many other countries.
The valve of Saputo et al has a number of disadvantages. The valve is highly prone to water leakage during attachment of the hose because the prong pushes open the drain plug during installation of the hose connector, before the hose itself has been connected. The stem connecting the drain plug also presents a weak point that is likely to break with repeated usage, such as would be experienced by an inflatable or portable pool, leading to likely loss of the plug. Further, there is difficulty with plug removal in any embodiment that does not employ the hose connector prong to push out the drain plug, because of pressure on the plug from the liquid in the container. Pulling on the plug pull tab to remove the plug under these circumstances exerts extreme stress on the plug pull tab and/or stem, increasing the likelihood of breakage and ultimate loss of the plug. In addition, the user is still required to put his or her hand into the water in order to plug or unplug the valve. A further disadvantage is that, if the hose and connector are left connected during use of the pool, the hose and connector will tend to leak water out of the pool because of leakage around the plug.
What has been needed, therefore, is a drain valve for liquid-container products that allows connection of a drainage hose, that prevents leakage of liquids from the container during installation of the drainage hose, that prevents leakage of liquids from the valve if the hose is left connected, that is not prone to breakage after repeated use, that does not require the user to put his or her hand in the water, and that is easy to operate under all conditions.